I like the explanation that concrete isn't set in stone so to speak: https://www.theguardian.com/science/2017/jul/04/why-roman-concrete-still-stands-strong-whil

I like the explanation that concrete isn't set in stone so to speak: https://www.theguardian.com/science/2017/jul/04/why-roman-concrete-still-stands-strong-while-modern-version-decays https://www.theguardian.com/science/2017/jul/04/why-roman-co...